As developments proceed in the telecommunications industry, demands arise for various kinds of test equipment specifically intended for test, repair and calibration of particular classes of equipment, such as, for example, cellular phones. We shall call such a piece of dedicated test equipment a "test set". Think of a test set as a unitary commercial version of a special purpose laboratory set-up involving a collection of separate instruments. A test set might even be of laboratory quality and intended for use primarily at the factory level. One capability that is very useful in a test set for telecommunications equipment is that of measuring RF power. And while there are many commercial RF power meters on the market, some with very wide ranges of frequency and power level, and all very accurate, it is generally not economical to include one of these as a component in a test set. A need exists for an economical method of including in a test set the ability to perform sensitive and accurate RF power measurements over a wide range of power levels and frequencies.